摘要
利用室内水槽测量海岸盐沼植物冠层水流平均流速分布 ,对a)不同属种、b)同属种不同观测位置和流速、c)同属种不同高度、d)同属种不同密度的海岸盐沼植物冠层湍流结构作了分析 ,并探讨了冠层植物本身及其水流结构对粘性泥沙运动的可能影响。实验结果揭示了冠层上、下水流的复杂性 :1)明显的三层结构 ,即冠层底部、过渡层、冠层上部水体层 ;2 )由于植物的柔弹性 ,冠层顶部与上层水体相互作用可能产生界面波 ,导致一个次级流速最大值 ,在冠层内出现流速反转梯度 ( u/ z) ;3 )冠层顶部以上的水体水流切变流速u (切应力τb)大于冠层内的u (切应力τb) ,冠层内 (底部 )水流切变流速 (切应力τb)的减小有利于粘性泥沙的沉积 ;4 )植物冠层影响湍流强度和扩散。
Mean velocity profiles of flow in and above the coastal saltmarsh canopy (different species, heights, densities and measurement locations) were measured in a flume. The results demonstrate the flow complexity in and above the canopy. Three layeres can be identified in the whole water column:within-the-canopy, transitional zone, and above-the-canopy. Due to the flexibility of plants, there is an interfacial wave resulting from the interaction between the canopy and overlying water. As a result, there is a reversal of flow velocity gradient in the lower part of the canopy, resulting in a secondary flow velocity maximum in the canopy. The shear velocity of flow above the canopy is greater than that within the canopy. The reduction of shear velocity within the canopy will favor the deposition of cohesive suspended sediment. The canopy exerts a strong influence on bed shear stress and turbulence of flow above and within the canopy.
出处
《海洋工程》
CSCD
北大核心
2001年第3期51-59,共9页
The Ocean Engineering
基金
国家自然科学基金资助项目 ( 494762 81)
国家教育部优秀青年教师基金资助项目
国家教育部跨世纪优秀人才培养计划基金资助项目
